Introduction Accumulating evidence challenges the belief that small intracranial aneurysms have a low risk of rupture.

Aim of Study The aim of this study was to identify the angiographic characteristics of ruptured aneurysms ≤7 mm and to assess their clinical significance.

Methods Retrospective analysis of 385 patients (149 unruptured, 236 ruptured). Two- and three-dimensional digital subtraction angiography evaluated aneurysm location, size parameters, angulations, morphology, and parent artery diameter.

Results Ruptured aneurysms were more common in the anterior communicating, posterior inferior cerebellar, and internal carotid termini. Ruptured aneurysms had greater height (AUC 0.60, p<0.01), and aneurysm angle (AUC 0.61, p=0.02) but smaller dome (AUC 0.44, p=0.02) and neck width (AUC 0.38, p<0.01). The calculation of size quotients improved the prediction of rupture: aspect ratio (AUC 0.77, p<0.01) and size ratio (AUC 0.76, p<0.01). Morphology became insignificant after adjustment (p=0.92).

Conclusion Small ruptured aneurysms often have an elongated and tilted shape, which is reflected by a high size and aspect ratio Identification of angiographic characteristics of small aneurysms aids in risk assessment and management strategies for unruptured aneurysms. Further studies are needed to determine optimal management approaches.

Disclosure of Interest CK serves as consultants for Acandis GmbH (Pforzheim, Germany) and proctor for MicroVention Inc./Sequent Medical (Aliso Viejo, CA, USA). David Zopfs is on the speaker’s bureau of Philips (Amsterdam, the Netherlands) and lecturer for Amboss GmbH (Cologne, Germany). The other authors declare that they have no competing interests.